Gas Valves draw 1.05 A & anticipator gives 6 min burns

Blackoakbob

actually read the amp draw on the red or R wire to the stat when the unit first turns on? Not seeing a wiring diagram it may be the easiest way to get a correct amp reading. If each gas valve is operated buy a vaporstat then the most even heating could be recieved buy using a 2-stage stat and setting the individual heat anticipators at the measured amp draw. Best Regards

Mike Valentine

T87F is over-anticipated with 1.05 A gas valve load

Hi All,

I'm a home owner and I had a new residential boiler installed by some real steam guys last year. They did a pretty good job, but live 1.5 hours away. The new boiler seemed to heat the house OK when they finished, but lately I've become a little more picky.

The new boiler has two Honeywell gas valves in series in a Hi/Lo fire arrangement. They are a V8943A1103 main on/off valve that draws 0.35 A and a V8944N1053 regulating valve that draws 0.70 A during High-fire. There are two Vaporstats that control the valves; one set to 10 ounces that controls the Hi-fire regulator and the other set to 11 ounces that controls the on/off valve.

My old boiler worked pretty well with the T87F anticipator set to 1.2A. I don't have the old valve to see how much current it consumed, but I strongly doubt that it was as high as 1.05 A.

The symptoms of the present arrangement are that the extremities of the radiator system do not heat well. The system only heats for 6 minutes, or so, per cycle. There seem to be about 5 cycles per hour at 25-30 degrees outside temperature. At the end of a cycle, the system pressure has only risen to 5 ounces, and the system never gets to go into lo-fire. The Vaporstats work fine when one shorts out the thermostat to test the basic qualities of the steam system.

My amateur diagnosis is that the thermostat is over-anticipating even though it is set to 1.2 (all the way to the left). I wish it could be set to about 3 or 4! The combination of 1.05 A at the beginning of the burn and the nature of a steam system conspire to make the anticipator setting an issue.

I'm thinking about switching thermostats to a T8775A and trying the once per hour or the three times per hour settings.

Can anyone think of something better to try?

Cheers,

Mike in Cincinnati

Empire_2

Help om the way

I'm sure that some of the steam heads will respond soon. I think that your 5 cycles per/hr is excessive and if your burner circuit is srawing over 1.2 amps,..that don't sound right. I understand that the burner is staged with 2 valves, but It should also be a 2 stage stat to seperate this hi draw for lo/hi fire. Since your current stat is cycling at about 5 cycles /sec, I think this is because of the hi amp draw on that stat. Just my thoughts...

Barbarossa

Have you put a amp meter in series with the t stat to confirm the amp draw.

soot_seeker_2

Yup.

I measured the current through the thermostat at 1.27 A, just now, with my trusty Fluke 87 multimeter.

That's even more than I thought it might be.